1. Field of the Invention
The invention relates to a heat exchanger with a heat exchanger block disposed between two collecting tanks, whereby the collecting tank has a cover and a tube bottom, whereby the tube bottom has upstanding edge regions.
2. Description of the Background Art
Heat exchangers, particularly those used in motor vehicles, normally have a radiator block made of tubes and ribs. The tubes are inserted in a tube bottom and connected to it. A collecting tank is connected to the tube bottom, which normally is made of a metallic material, particularly aluminum.
The collecting tank, which in many cases is made of a plastic, is fixed to the tube bottom by a mechanical connection. To assure a fluid-tight connection between the collecting tank and the tube bottom, a seal is inserted between the tube bottom and collecting tank.
The seal between the collecting tank and tube bottom is compressed by the mechanical connection of the collecting tank with the tube bottom.
The connection between the collecting tank and the tube bottom is exposed to alternating loads by the operation of a heat exchanger. This occurs because of the internal pressure in the heat exchanger. With an increasing operating life of the heat exchanger, there is the risk that the joint between the collecting tank and tube bottom becomes untight. This can be caused, for example, by the deformation of the mechanical connection.
DE 28 52 408 A1, which corresponds to U.S. Pat. No. 4,331,201, discloses a so-called corrugated slotted flanging. The tube bottom in this case has slots in the upstanding edge region. For connection with the collecting tank, the material is pressed over the slots inwardly toward the collecting tank. The inwardly pressed areas thereby engage via a pressed down peripheral flange of the collecting tank, as a result of which the tank is attached. In the case of high loads due to the arising internal pressures, it can happen that the outer wall is pressed outwardly especially along the long sides of the collecting tank and bends the tube bottom or the mechanical retaining elements of the tube bottom, as a result of which there no longer is a sufficient sealing effect.
DE 43 38 055 A1 discloses a similar solution. In addition, hooks of the collecting tank here engage behind the tube bottom from outside. Said hooks are intended to produce an additional stabilizing effect particularly along the long side of the collecting tank.
The insufficient durability in particular of the connection between the tube bottom and collecting tank in the state of the art is disadvantageous.